With the popularization of the Internet, the opportunity of delivering a content to various types of information terminals which display information is increasing. Each of the information terminals has a monitor such as a display for a personal computer, television, etc. having a size of 10 inches or more, and a display for a PHS, a personal digital assistant (PDA), etc. having a size of about a several inches, and the like, and the ubiquitous information environment wherein the information is utilized without being conscious of the computer in any place in real life has been created.
Because the information terminals are of great variety and usable applications thereof differ from one another depending on the type of the information terminal, when a content stored in a server is delivered to the information terminals, an error occurs in displaying the information (content) in some cases. Therefore, it is necessary to subject an HTML document to shaping and format conversion, and such technology is called transcoding.
Particularly, in the case of delivering an image to various information terminals, it is necessary to perform a color conversion in accordance with performances such as the number of colors and a resolution of a display of each of the information terminals and, further, to perform an image format conversion which enables the image to be displayed by the application of each of the information terminals. For example, JP-A-2002-108757 proposes a method of image conversion, wherein a content image is reduced in size after being rotated in view of an aspect ratio so that the image is displayed on a screen having a lower resolution such as that of a mobile terminal. Further, as disclosed in JP-A-9-233490, a color management technology wherein a color conversion is performed in accordance only with color characteristics of each of information terminals is known. In the color management, color image data are output after being converted into optimum color image data in such a manner that the color image data input from an input unit such as a camera and a scanner is converted into an independent color space which does not rely on the input unit before being displayed on a display of each of the information terminals.
Since each of these conventional image conversions performed in an information processer consists only of the aspect ratio conversion in accordance with a display of the information terminal, the resolution conversion with respect to a reduction in image size, and the reduction of color number conversion such as a halftone conversion, the image displayed on the monitor having the size of a several inches, such as that of a mobile terminal, is undesirably reduced in quality and texture as compared with the original image accumulated in server, resulting in an indistinct image.
For example, when a fine texture of an object is subjected to a simple resolution reduction, the texture is displayed differently from that observed when the size is the standard size. Further, the above problems are not solved by the conventional color management technology since the technology is oriented only to color characteristics of the display without considering the resolution and so forth.
Also, since the color management technology is used for compensating only the color characteristics of the image input/output unit such as a camera and a display, the technology is not yet capable of outputting exact colors of the original image.